Interactive literature is a story you read and simultaneously direct: the text describes what's happening, and you choose what to do or say next. There may be little or no graphics — the main focus is on the plot, characters, and the consequences of your decisions. The genre is similar to the gamebooks many remember from childhood.
It's similar, but visual novels feature more illustrations and characters onscreen. Interactive fiction emphasizes text — like a book you co-author.
Any of these games can be downloaded via torrent, repack, portable version, or GOG release.